ffsim.GivensAnsatzOp¶

class ffsim.GivensAnsatzOp(norb, interaction_pairs, thetas, phis, phase_angles)[source]¶

A Givens rotation ansatz operator.

The Givens rotation ansatz consists of a sequence of Givens rotations followed by a layer of single-orbital phase gates.

Note that this ansatz does not implement any interactions between spin alpha and spin beta orbitals.

norb¶

The number of spatial orbitals.

interaction_pairs¶

The orbital pairs to apply the Givens rotations to.

thetas¶

The angles for the Givens rotations.

phis¶

The optional phase angles for the Givens rotations.

phase_angles¶

The optional phase angles for the layer of single-orbital phase gates.

Methods

`from_orbital_rotation`(orbital_rotation)	Initialize the operator from an orbital rotation.
`from_parameters`(params, norb, interaction_pairs)	Initialize the operator from a real-valued parameter vector.
`n_params`(norb, interaction_pairs[, ...])	Return the number of parameters of an ansatz with given settings.
`to_orbital_rotation`()	Convert the Givens ansatz operator to an orbital rotation.
`to_parameters`()	Convert the operator to a real-valued parameter vector.

static from_orbital_rotation(orbital_rotation)[source]¶

Initialize the operator from an orbital rotation.

static from_parameters(params, norb, interaction_pairs, with_phis=True, with_phase_angles=True)[source]¶

Initialize the operator from a real-valued parameter vector.

Parameters:

params (ndarray) – The real-valued parameter vector.
norb (int) – The number of spatial orbitals.
interaction_pairs (list[tuple[int, int]]) – The orbital pairs to apply the Givens rotation gates to.
with_phis (bool) – Whether to include complex phases for the Givens rotations.
with_phase_angles (bool) – Whether to include a layer of single-orbital phase gates.

Return type:

GivensAnsatzOp

static n_params(norb, interaction_pairs, with_phis=True, with_phase_angles=True)[source]¶

Return the number of parameters of an ansatz with given settings.

Parameters:

norb (int) – The number of spatial orbitals.
interaction_pairs (list[tuple[int, int]]) – The orbital pairs to apply the Givens rotation gates to.
with_phis (bool) – Whether to include complex phases for the Givens rotations.
with_phase_angles (bool) – Whether to include a layer of single-orbital phase gates.

Return type:

int

to_orbital_rotation()[source]¶

Convert the Givens ansatz operator to an orbital rotation.

to_parameters()[source]¶

Convert the operator to a real-valued parameter vector.

Attributes